Noble metals have heretofore been suggested for use and/or have been utilized in connection with diverse types of devices, including, for example, use of a layer of noble metal in connection with devices providing high reflectivity.
While use of a layer of a noble metal has proved to be superior, at least in some respects, to use of a layer of other metals in connection with many diverse types of devices, including devices as above mentioned, such use of noble metals has not, however, proved to be completely satisfactory, particularly in resisting damage to the noble metals, such as, for example, not adequately resisting damage arising from exposure of the noble metals to environmental conditions and/or abrasion.
Over coating layers have also heretofore been suggested for use and/or have been utilized in connection with metals in an attempt to provide protection for and/or to enhance reflectivity of the metals, including, for example, providing an oxide over coating for aluminum reflectors (see "Aluminum mirrors Al.sub.2 O.sub.3 -protected, with high reflectance at normal but greatly decreased reflectance at higher angles of incidence in the 8-12 .mu.m region", by Cox and Hass, Applied Optics, Vol. 17, No. 3, pages 333-334, February 1978).
Over coating has, however, often proved to be inadequate to solve the problem when used with noble metals, clue, at least in part, to the over coating failing to satisfactorily bond, or otherwise adhere, to the noble metal. In particular, it has been found that a layer, or layers, of dielectric material often do not adhere well to noble metals and, when so used, degrade and/or delaminate over time resulting in degradation of reflectivity and/or of the over coating layer, or layers.
Bonding layers have heretofore been suggested for use in conjunction with a noble metal reflector (see "Reflectance and durability of Ag mirrors coated with thin layers of Al.sub.2 O.sub.3 plus reactively deposited silicon oxide", Hass et al., Applied Optics, Vol. 14, No. 11, pages 2639-2644, November 1975), and it has heretofore been observed that an over coating layer can form an intermetallic alloy when used in conjunction with a metal such as a noble metal (see "Deterioration of Reflecting Coatings by Intermetallic Diffusion", Hunter et al., Applied Optics, Vol. 11, No. 7, pages 1594-1597, July 1972).
It is felt, however, that improved devices and/or methods are still needed for protecting and/or enhancing reflectivity of noble metal.